The big one is due

By ILANA TEITELBAUM

November 14, 2007 10:21

A large earthquake would be devastating, but taking the proper precautions now can minimize the damage.

quake 88.
(photo credit: )

Most Israelis can remember a day when their furniture started to shake, and can also take credit for surviving that day with little difficulty. But very few people are in a position to know firsthand the effects of a truly disastrous earthquake, on a magnitude of seven or higher on the Richter scale, as the last recorded such earthquake in Israel occurred in 1033.
And that's the problem: Geology experts agree that Israel is long overdue for the next "Big One," and it can happen at any time. This poses a significant threat to population centers in the country, since many buildings in Israel were erected prior to the formulation of earthquake-resistant construction codes. There is also substantial doubt that the codes are being strictly enforced. With the barrage of immediate threats competing for Israelis' attention - whether terrorism, car accidents, global warming or secondhand smoke - a major earthquake may seem like an improbable, even paranoid fear.
While predicting the time of the next earthquake is nearly impossible, says Dr. Amos Salamon of the Israel Geological Survey, "We know one thing - we are sure there will be an earthquake in Israel."
This is because Israel is situated on two significant fault lines: the Dead Sea Fault and the Carmel Fault. To understand which parts of the country would be most vulnerable to a major earthquake, geologists must base their knowledge on previous events - and in this case, modern technology is of surprisingly little help.
"In modern times we usually monitor earthquakes by using seismographs," explains geologist Dr. Shmuel Marco of Tel Aviv University.
But seismographs have only existed for about a century, whereas geological processes develop over thousands, if not millions of years. Therefore, there is a dearth of information on the major earthquakes in Israel's past - and such information could be crucial to determining which areas in Israel are in greatest danger.
This is especially true of the Carmel Fault, which poses a threat to Haifa, among other places. Because the fault has been dormant in the recent past, its potential threat is unknown.
For that reason, Marco has made it his mission to build a timeline of Israel's earthquakes by delving into history and archeology, in addition to geology. On the historical side, Marco has studied hundreds of ancient documents that contain references to earthquakes, in translations from the original Greek, Latin and Arabic. The originals of some of these documents are assumed to reside in the Vatican vaults. Even the Bible offers clues, as earthquakes are sometimes mentioned as markers of time, Marco explains. For example, prophets are often said to have become active a certain number of years "after the earthquake."
With the aid of these documents, Marco has helped determine that a series of devastating earthquakes hit Israel in the past two thousand years. The major ones were recorded in the Jordan Valley in the years 31 BCE, 363 CE, 749 CE and 1033 CE, "so roughly," says Marco, "we are talking about an interval of every 400 years. If we follow the patterns of nature, a major quake should be expected any time because almost a whole millennium has passed since the last strong earthquake."
Marco also uses archeological excavations to learn more about the country's earthquake trends. For example, he is participating in the excavation of Megiddo, the site of an ancient Canaanite city situated on the Carmel Fault. He and geologist Prof. Amotz Agnon of the Hebrew University are analyzing findings on the site, together with archeologist Prof. Israel Finkelstein.
The geologists' focus on the archeological site stems from the hope that archeological evidence will provide clues to the 5,000-year-old city's geological past. The geological history of Megiddo would have ramifications for the entire region situated atop the Carmel Fault, Finkelstein explains.
"At Megiddo there's a sequence of cities. If one can keep track of the earthquakes that damaged these cities, one can establish a timeline of earthquakes in the north," he says.
Megiddo is an ideal candidate for such research because it is a site with many layers of history, and each layer tells its own story of the damage that took place. The most important - and only conclusive - piece of evidence that researchers have discovered so far in the investigation of the mystery that is the Carmel Fault, is damage to a monumental temple, says Finkelstein, which corresponds to a biblical reference to a major earthquake that occurred in the late fourth millennium.
The nature of earthquakes is that they result from a buildup of tension in the earth's crust along fault lines. The longer the period between earthquakes, the more tension builds, with catastrophic consequences upon its release. Since the last major earthquake was 1,000 years ago, "We are now in a deficit," Marco explains. "There's been no release of tension, just buildup. It's like if you have a strip of rubber between your hands and keep pulling it - you know that it's going to snap eventually."
WHERE IS the next big quake most likely to hit? "We think that the focus of major earthquakes will be in and around the Dead Sea Fault. The seismic waves will spread around the epicenter and they will affect buildings far away from the focus," says Salamon.
Places along the Dead Sea Fault include Eilat, towns in the North, Kiryat Shmona, Tiberias and Beit She'an. "According to the historical records we have, almost every place in Israel was damaged several times in history [by earthquakes]," Salamon says. This is because places that are not directly above the fault but are relatively close to it, like Jerusalem, are still vulnerable to the effects of an earthquake.
Tel Aviv is a good distance away from the fault and therefore may not incur heavy damage, but on the other hand, Marco says that there is evidence of earthquake damage to ancient Jaffa, possibly as a result of activity along the Carmel Fault.
How much damage can we expect from the next earthquake? Salamon explains that the extent of damage is determined by "a combination of the effect of the earthquake and the strength of buildings."
Marco agrees that building quality is the most important factor in preparing the country for an earthquake. "If you're out in a football field, even a monster earthquake will not do any damage to you physically. You might need a psychologist, but not a physician," he says. "If you're in a building, your life depends on the quality of construction."
Marco adds that in other parts of the world such as the US and Japan, where the risk of earthquakes is high, seismic codes are strictly adhered to. "All the skyscrapers in America are built with some flexibility, so they're not too stiff," he explains. "Small or even large earthquakes would make them sway a little, but not collapse."
The good news is that since 1975, Israel has instituted building codes that are on par with international standards, in particular those of California. Additionally, these codes have been revised and improved over decades of accumulated research.
The question is whether these laws are actually enforced, and in that regard, the issue becomes more uncertain. Building regulations are issued at a national level by the interior minister, but the responsibility for enforcement lies with local authorities. While Interior Ministry spokesman David Pilzer states that building codes are much improved and awareness of the problem is higher than it was, he says that local enforcement of the codes "varies from place to place."
The reason for this variance, he explains, has to do with the seismic calculations for buildings, which are the diagrams drawn up before a building is approved to demonstrate its resistance to earthquakes. These calculations are submitted to the local authorities before a construction plan is accepted. But there's a snag, says Pilzer, which is that most local authorities don't have professional engineers on staff to check the calculations.
Even if the current building codes are enforced, that still leaves the problem of older buildings that predate the 1975 laws. Pilzer agrees that the prevalence of old buildings that do not comply with current standards is a "substantial" problem.
Pilzer is a member of the Steering Committee for Earthquake Preparedness in Israel, which was founded in 1999 in response to the earthquake that year in Turkey. The committee comprises a diverse assortment of government officials and researchers, and is responsible for preparing the country for an earthquake. Such preparation extends as far as training the IDF in search-and-rescue missions, as well as in the retrieval and identification of casualties.
The steering committee is also responsible for revising building codes as more information in the field of seismic resistance is discovered.
Even though geological discoveries are made all the time, enforcing the corresponding changes to building codes is another story. "I don't think [the municipal authorities] have enough manpower to physically check that things are done according to the building codes," says committee chairman Yael Kligman. "The engineer who plans the building has to sign and commit, but most of the time no one else is checking."
ENFORCING BUILDING codes might seem daunting, but the issue of unsafe older buildings is even more problematic. Geologist Dr. Hillel Wust-Bloch, one of whose chief interests is earthquake prevention, says that a large problem is that in places such as Beit She'an, Kiryat Shmona and Tiberias - situated directly on the Dead Sea Fault - there are entire neighborhoods built in the '40s and '50s that are "cheap and vulnerable." Additionally, cities like Jerusalem and Tiberias are rife with older buildings.
To counter this problem, the government instituted National Outline Plan 38, a program granting extra building rights to people living in pre-1980 buildings. Within these rights they are allowed the construction of additions such as elevators, balconies or a penthouse, adding value to the building.
"The concept is that the additions to the buildings provide revenue, which can be used to strengthen the building," explains Pilzer.
One of the ways in which a building can be strengthened is by enclosing its first floor. Many older buildings in Israel are built on columns, which geologists say are an obvious hazard.
Plan 38 is currently being implemented in small sections of Tel Aviv and Jerusalem, in the latter case as an "experiment" according to the Jerusalem Municipality. There are a number of obstacles to putting the plan into action on a broad scale, which Pilzer is hoping will be solved with the introduction of additional incentives, such as tax breaks.
One of the reasons the plan has not been widely implemented is that contractors are waiting for these incentives to be issued. Additionally, at the present time a building can only take advantage of Plan 38 if 75 percent of a building's residents consent. Pilzer says that there is legislation under way to reduce that figure to 50 percent.
At a recent interministerial committee, incentive recommendations were made that included granting low-interest loans for strengthening buildings, says Pilzer. But this idea is controversial because of the large costs involved, particularly when there are higher financial priorities, he says.
As explained above, the success of Plan 38 is tied to the revenue that is generated by the building additions. So what about places like Beit She'an and Kiryat Shmona, where property prices are relatively low?
"That is still a problem," admits Kligman. Pilzer suggests that in such places, erecting entirely new buildings would be of little cost - but such a measure has not been implemented.
In addition to building safety concerns, Marco cites the chemical industries in Haifa as a potential threat, estimating that the breakage of one ammonia tank in the event of an earthquake would result in the deaths of 10,000 people. However, Kligman is quick to point out that the earthquake preparedness steering committee has charged the Environmental Protection Ministry with the task of checking the resistance of chemical containers in factories.
Even if a building is earthquake safe, there are additional measures people can take to protect themselves. For example, Wust-Bloch, who visits schools to teach earthquake preparedness, instructs students to get under a table and hold onto the legs (otherwise the table may slide away), or to protect their heads with their school bags. Also, one should keep shoes by the bed because if there is an earthquake in the night, the floor around the bed will be littered with broken glass. Wust-Bloch also recommends bolting the fridge to the floor, so that it doesn't topple.
Still, none of these measures are worthwhile if buildings aren't secure, and both Marco and Wust-Bloch believe that building safety in Israel is a matter for concern.
While Marco acknowledges that retrofitting all the buildings in the country is preventively expensive, he says "We need money for research that will tell engineers where to start, and which parts of the country are more dangerous. We want to know if we should reinforce first in Kiryat Shmona, Tiberias or Eilat.
"This is a heavy question," he continues. "It's impossible to enslave the entire country's budget to retrofitting, but we need to start somewhere. We should start from the most urgent place."
Israel's lack of progress in building safety is particularly bewildering in light of the standards maintained elsewhere in the world, he adds.
"The civilized state that we want to be should earmark some money for this kind of research, that is not only scientific but also applicable," concludes Marco. "We can and should do better."

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